A light source device includes a substrate and a light source. The light source includes a first light emission unit, a plurality of second light emission units, and a plurality of third light emission units arranged two-dimensionally on the substrate. The first light emission unit is arranged at a center among the light emission units, and includes a first light emission element having a first light emission face. The second light emission units surround the first light emission unit, and include a plurality of second light emission elements, respectively, each having a second light emission face. The third light emission units surround the second light emission units, and include a plurality of third light emission elements, respectively, each having a third light emission faces. The first light emission face and the second light emission faces all have the same areas. The third light emission faces have different areas.